Drive apparatus

ABSTRACT

A drive apparatus includes a motor that includes a motor shaft disposed along a first central axis that extends in one direction, a housing that includes a first housing portion housing the motor and that is capable of storing oil, and a liquid cooling portion disposed in thermal contact with an inverter electrically coupled to the motor, the liquid cooling portion including a refrigerant liquid flowing therein. The housing includes a contact portion with which the liquid cooling portion is in thermal contact. At least a portion of the contact portion is disposed below an oil surface of the oil stored in the housing.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to a drive apparatus.

2. Description of the Related Art

A rotary electric machine including a case that stores a lubricatingfluid that lubricates and cools a stator, a rotor, and the like isknown.

In such a rotary electric machine described above, it is desirable thata temperature of the lubricating fluid is lowered by cooling thelubricating fluid supplied to the stator and the like so that the statorand the like are efficiently cooled. As a method of cooling thelubricating fluid supplied to the stator and the like, one can conceiveof a method in which, for example, a cooling device is provided midwayof an oil passage supplying the lubricating fluid stored in a case tothe stator and the like and cooling the lubricating fluid with thecooling device.

However, with the above method, there are cases in which the lubricatingfluid is not sufficiently cooled since the lubricating fluid is onlycooled while passing through the cooling device. Furthermore, since thecooling device that cools the lubricating fluid needs to be providedseparately, there is a problem in that the rotary electric machinebecomes large in size.

SUMMARY OF THE INVENTION

A drive apparatus according to an example embodiment of the presentdisclosure includes a motor that includes a motor shaft disposed along afirst central axis that extends in one direction, a housing thatincludes a first housing portion housing the motor and that is capableof storing oil, and a liquid cooling portion disposed in thermal contactwith an inverter electrically coupled to the motor, the liquid coolingportion including a refrigerant liquid flowing therein. The housingincludes a contact portion with which the liquid cooling portion is inthermal contact. At least a portion of the contact portion is disposedbelow an oil surface of the oil stored in the housing.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a drive apparatus of a firstexample embodiment of the present disclosure.

FIG. 2 is a perspective view illustrating the drive apparatus of thefirst example embodiment of the present disclosure.

FIG. 3 is a drawing illustrating the drive apparatus of the firstexample embodiment of the present disclosure and is a partialcross-sectional view taken along line III-III in FIG. 2.

FIG. 4 is a perspective view schematically illustrating a portion of thedrive apparatus of the first example embodiment of the presentdisclosure.

FIG. 5 is a drawing illustrating portions of bus bars of the firstexample embodiment of the present disclosure.

FIG. 6 is a drawing illustrating a cooling portion of the first exampleembodiment of the present disclosure in is a cross-sectional view takenalong line VI-VI in FIG. 4.

FIG. 7 is a partial cross-sectional view illustrating a drive apparatusof a second example embodiment of the present disclosure.

FIG. 8 is a perspective view schematically illustrating a portion of thedrive apparatus of the second example embodiment of the presentdisclosure.

FIG. 9 is a perspective view schematically illustrating a portion of adrive apparatus that is a modification of the second example embodimentof the present disclosure.

FIG. 10 is a perspective view schematically illustrating a portion of adrive apparatus of a third example embodiment of the present disclosure.

FIG. 11 is a perspective view schematically illustrating a portion of adrive apparatus of a fourth example embodiment of the presentdisclosure.

FIG. 12 is a cross-sectional view illustrating a cooling portion that isanother example embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A Z-axis direction illustrated as appropriate in each of the drawings isa vertical direction Z in which a positive side is the upper side and anegative side is the lower side. A Y-axis direction is a directionorthogonal to the Z-axis direction. An X-axis direction is a directionorthogonal to both the Z-axis direction and the Y-axis direction. TheY-axis direction is equivalent to a first direction. A negative side inthe Y-axis direction is equivalent to a first side in the firstdirection. In the following description, the Y-axis direction is merelyreferred to as “a first direction Y”, and the negative side in theY-axis direction is referred to as “a first direction first side” andthe positive side in the Y-axis direction is referred to as “a firstdirection second side”.

Furthermore, the X-axis direction is one direction in which a firstcentral axis J1, which is illustrated as appropriate in each drawing,extends. In other words, an axial direction of the first central axis J1is a direction orthogonal to both the vertical direction Z and the firstdirection Y. In the following description, the X-axis direction ismerely referred to as “an axial direction X”, and the negative side inthe X-axis direction is referred to as “an axial direction first side”and the positive side in the X-axis direction is referred to as “anaxial direction second side”. Furthermore, a radial direction having thefirst central axis J1 as the center is merely referred to as “a radialdirection” and a circumferential direction about the first central axisJ1 is merely referred to as “a circumferential direction”.

Note that the vertical direction, the left side, and the right side aremerely terms for describing the positional relationship of the members,and the actual dispositional relationship and the like may be adispositional relationship and the like that is different from thedispositional relationship and the like that is depicted by the aboveterms.

As illustrated in FIGS. 1 to 4, a drive apparatus 10 of the presentembodiment includes a housing 20, a motor 30, an inverter unit 40, busbars 70, a liquid cooling portion 50, pipe portions 61 and 62, and adifferential gear 80. The housing 20 houses the motor 30 and thedifferential gear 80. As illustrated in FIG. 3, the housing 20 includesa first housing portion 21 and a second housing portion 22.

The first housing portion 21 houses the motor 30. The first housingportion 21 includes a cylindrical portion 21 a and a protruding portion21 b. The cylindrical portion 21 a has a substantially cylindrical shapethat extends in the axial direction X. The protruding portion 21 bprotrudes downwards and is slightly inclined towards the first directionfirst side in FIG. 3 from the cylindrical portion 21 a. A sectionalshape of the protruding portion 21 b orthogonal to the axial direction Xis a trapezoidal shape in which the width thereof becomes smaller as thetrapezoidal shape becomes distanced away from the cylindrical portion 21a.

In the following description, a direction parallel to the direction inwhich the protruding portion 21 b protrudes is referred to as aprotrusion direction P and is depicted as a P -axis direction in each ofthe drawings. The protrusion direction P is a direction slightlyinclined against the vertical direction Z towards the first directionsecond side. Furthermore, a direction orthogonal to both the protrusiondirection P and the axial direction X is referred to as a widthdirection W and is depicted as a W-axis direction in each of thedrawings. The width direction W is a direction inclined slightlydownwards against the first direction Y. Furthermore, the positive sideof the protrusion direction P is referred to as a protrusion directionupper side and the negative side of the protrusion direction P isreferred to as a protrusion direction lower side.

Note that in the drawings that illustrate the protrusion direction P asan up-down direction such as, for example, FIG. 4 and the like, an oilsurface OS1 of oil O is schematically depicted as a state in which theprotrusion direction P is parallel to the vertical direction Z. In otherwords, in the drawings that illustrate the protrusion direction P as theup-down direction, the oil surface OS1 of the oil O is depicted as asurface orthogonal to the protrusion direction P.

The second housing portion 22 houses the differential gear 80. Asillustrated in FIGS. 1 and 2, the second housing portion 22 is disposedon the axial direction second side of the first housing portion 21. Asillustrated in FIGS. 2 and 3, the second housing portion 22 extends inthe first direction Y and protrudes on the first direction second sidewith respect to the first housing portion 21. Although not shown, aninner portion of the first housing portion 21 and an inner portion ofthe second housing portion 22 are connected by a connection portionbetween the first housing portion 21 and the second housing portion 22,in other words, are connected at an end portion of the first housingportion 21 on the axial direction second side. A lower end portion ofthe second housing portion 22 is disposed below a lower end portion ofthe first housing portion 21.

As illustrated in FIG. 3, the housing 20 is capable of storing the oilO. In the present embodiment, each of the first housing portion 21 andthe second housing portion 22 is capable of storing oil O. In FIG. 3,the oil surface OS1 of the oil O stored in the first housing portion 21is positioned above an oil surface OS2 of the oil O stored in the secondhousing portion 22.

The motor 30 includes a motor shaft 31 disposed along the first centralaxis J1 extending in one direction, that is, the axial direction X, arotor core 32, and a stator 33. The rotor core 32 is fixed to the motorshaft 31. The rotor core 32 has an annular shape fixed on an outerperipheral surface of the motor shaft 31. The rotor core 32 is disposedabove the oil surface OS1 of the oil O stored in the first housingportion 21. Accordingly, the rotor core 32 can be prevented from beingsoaked in the oil O stored in the first housing portion 21. With theabove, the oil O can be prevented from being a rotational resistance ofthe rotor core 32 when the rotor core 32 rotates.

In the present embodiment, the upper limit of the oil surface OS1 of theoil O in the first housing portion 21 is an oil surface upper limit OS1a indicated by a two-dot chain line illustrated in FIG. 3, for example.The oil surface upper limit OS1 a is in contact with a lower edge of therotor core 32. For example, when the drive apparatus 10 is driven andthe differential gear 80 is rotated, the oil O stored in the secondhousing portion 22 is stirred upwards with the gear of the differentialgear 80 and flows into the first housing portion 21. With the above, theamount of oil O stored in the first housing portion 21 is increased andthe oil surface OS1 of the oil O stored in the first housing portion 21is risen. Even in such a case as well, in the present embodiment, theoil surface OS1 of the oil O does not rise above the oil surface upperlimit OS1 a.

The stator 33 opposes the rotor core 32 in the radial direction with agap in between. The stator 33 surrounds a radial direction outer side ofthe rotor core 32. The stator 33 includes a stator core 34 and aplurality of coils 35. The stator core 34 includes an annular-shapedcore back 34 a, and a plurality of teeth 34 b extending inwardly in theradial direction from the core back 34 a. The core back 34 a is fixed toa radial direction inner lateral surface of the first housing portion21. The plurality of coils 35 are mounted in the stator core 34. Morespecifically, the plurality of coils 35 are each mounted on acorresponding one of the plurality of teeth 34 b.

The inverter unit 40 is electrically coupled to the motor 30. Theinverter unit 40 controls the electric current fed to the motor 30. Asillustrated in FIGS. 1 and 2, the inverter unit 40 is fixed to an outerlateral surface of the housing 20. As illustrated in FIG. 1, theinverter unit 40 includes a first unit 41 and a second unit 42. Asillustrated in FIG. 3, the first unit 41 is fixed to a lower portion ofthe first housing portion 21. The first unit 41 includes a firstinverter case 41 a and a first inverter portion 43. In other words, theinverter unit 40 includes the first inverter portion 43.

As illustrated in FIGS. 1 and 3, the first inverter case 41 a has asubstantially cubic box shape. As illustrated in FIG. 3, the firstinverter case 41 a is fixed to a radial direction outer lateral surfaceof the first housing portion 21 and extends towards the protrusiondirection lower side from the first housing portion 21. The lowerportion of the first housing portion 21 is housed inside the firstinverter case 41 a. In more detail, a portion of the cylindrical portion21 a on the protrusion direction lower side and the protruding portion21 b are housed inside the first inverter case 41 a.

The first inverter portion 43 is housed inside the first inverter case41 a. The first inverter portion 43 is installed on a bottom surface ofthe first inverter case 41 a. The first inverter portion 43 includes arectangular parallelepiped box -shaped case 43 a and a plurality ofpower devices 43 b housed inside the case 43 a. The case 43 a is open onthe protrusion direction upper side. An opening of the case 43 a isclosed by a heat sink described later. The power devices 43 b areattached to a surface of the heat sink 55 on the protrusion directionlower side. A heat generating amount of the power devices 43 b isrelatively large and, for example, is the largest among the elementsincluded in the inverter unit 40.

The second unit 42 includes a second inverter case 42 a, a secondinverter portion 44, and a connector portion 45. In other words, theinverter unit 40 includes the second inverter portion 44. As illustratedin FIG. 1, the second inverter case 42 a has a substantially cubic boxshape. The second inverter case 42 a is fixed to the radial directionouter lateral surface of the first housing portion 21 and extendssubstantially towards the first direction first side from the firsthousing portion 21. An edge portion of the first housing portion 21 onthe first direction first side is housed inside the second inverter case42 a. A lower end portion of the second inverter case 42 a is connectedto an edge portion of the first inverter case 41 a on the firstdirection first side. An inner portion of the second inverter case 42 ais connected to an inner portion of the first inverter case 41 a at aportion connected to the first inverter case 41 a.

As illustrated in FIG. 3, the second inverter portion 44 is housedinside the second inverter case 42 a. The second inverter portion 44 is,in the first direction Y orthogonal to the vertical direction Z,disposed on the first direction first side of the first housing portion21. Although not shown, the second inverter portion 44 is electricallycoupled to the first inverter portion 43. In the present embodiment,elements included in the second inverter portion 44 are elements inwhich heat generating amounts thereof are relatively small or areelements that do not generate heat.

The connector portion 45 protrudes upwards from an upper surface of thesecond inverter case 42 a. An external power supply (not shown) iscoupled to the connector portion 45. Power is fed to the first inverterportion 43 and the second inverter portion 44 through the external powersupply coupled to the connector portion 45.

As illustrated in FIG. 4, the bus bars 70 each have a rod shapeextending in the protrusion direction P. End portions of the bus bars 70on the protrusion direction lower side are electrically coupled to thefirst inverter portion 43. The bus bars 70 extend from the firstinverter portion 43 towards the protrusion direction upper side and passinside the housing 20. The bus bars 70 are provided in plural numbersand are aligned in the width direction W. Three bus bars 70 are, forexample, provided in FIG. 4.

As illustrated in FIG. 5, crimped terminals 71 are fixed to the endportions of the bus bars 70 on the protrusion direction upper side. Thecrimped terminals 71 are fixed to the bus bars 70 by being fastened withscrews, for example. Note that the crimped terminals 71 may be fixed tothe bus bars 70 by welding or the like. Pieces of conducting wire 35 aare coupled to the crimped terminals 71. The pieces of conducting wire35 a are end portions of pieces of conducting wire constituting thecoils 35. With the above, the bus bars 70 are coupled to the coils 35through the crimped terminals 71 and electrically couple the inverterunit 40 and the motor 30 to each other. Note that the pieces ofconducting wire 35 a may be other wiring members electrically coupled tothe coils 35.

As illustrated in FIG. 4, the end portions of the bus bars 70 on theprotrusion direction upper side are disposed on the protrusion directionupper side with respect to the oil surface OS1 of the oil O. With theabove, the crimped terminals 71 are disposed above the oil surface OS1of the oil O stored in the first housing portion 21, in other words, aredisposed above the oil surface of the oil O stored in the housing 20.Accordingly, even when vibration is applied to the drive apparatus 10and the oil O stored in the first housing portion 21 is agitated, forexample, the crimped terminals 71 are not easily affected by the oil O.With the above, the connections between the bus bars 70 and the piecesof conducting wire 35 a can be prevented from being disconnected.

The liquid cooling portion 50 cools the inverter unit 40. As illustratedin FIG. 3, the liquid cooling portion 50 in the present embodiment ishoused inside the first inverter case 41 a. The liquid cooling portion50 is fixed to the lower end portion of the first housing portion 21.The liquid cooling portion 50 is disposed below the rotor core 32. Asillustrated in FIG. 6, the liquid cooling portion 50 includes a case 51,the heat sink 55, and a wall portion 52. As illustrated in FIG. 3, thecase 51 has a rectangular parallelepiped box shape that is open on theprotrusion direction lower side. An opening of the case 51 on theprotrusion direction lower side is closed by the heat sink 55.

The case 51 includes a plate-shaped top plate portion 51 a orthogonal tothe protrusion direction P. The top plate portion 51 a opposes the heatsink 55 in the protrusion direction P with a gap in between. The topplate portion 51 a is in thermal contact with and is fixed to a surfaceof the protruding portion 21 b on the protrusion direction lower side.The protruding portion 21 b in the present embodiment is equivalent to acontact portion with which the liquid cooling portion 50 is in thermalcontact. In other words, the housing 20 includes the protruding portion21 b serving as a contact portion with which the liquid cooling portion50 is in thermal contact.

Note that in the present specification, any objects that are “in thermalcontact” with each other includes a case in which the objects aredirectly in contact with each other and a case in which the objects arein contact with each other through a heat transfer member. The heattransfer member includes, for example, silicon, a compound, thermaltape, grease, or the like.

The heat sink 55 includes a bottom plate portion 55 a and a plurality offins 55 b. The bottom plate portion 55 a has a plate shape orthogonal tothe protrusion direction P. A surface of the bottom plate portion 55 aon the protrusion direction lower side is a surface of the liquidcooling portion 50 on the protrusion direction lower side. The bottomplate portion 55 a closes the opening of the case 51 on the protrusiondirection lower side and also closes the opening of the case 43 a on theprotrusion direction upper side. In other words, the bottom plateportion 55 a partitions an inner portion of the liquid cooling portion50 and an inner portion of the first inverter portion 43 from each otherin the protrusion direction P.

The case 43 a and the power devices 43 b are fixed to the surface of thebottom plate portion 55 a on the protrusion direction lower side. Inother words, the first inverter portion 43 is fixed to the bottom plateportion 55 a. With the above, the liquid cooling portion 50 is disposedso as to be in thermal contact with the inverter unit 40. The pluralityof fins 55 b each have a rod shape projecting towards the protrusiondirection upper side from a surface of the bottom plate portion 55 a onthe protrusion direction upper side. End portions of the fins 55 b onthe protrusion direction upper side are disposed at positions separatedtowards the protrusion direction lower side from the top plate portion51 a of the case 51. As illustrated in FIG. 6, the plurality of fins 55b are disposed so as to be aligned in the width direction W and theaxial direction X.

The wall portion 52 extends towards the protrusion direction upper sidefrom the surface of the bottom plate portion 55 a on the protrusiondirection upper side and is connected to a surface of the top plateportion 51 a on the protrusion direction lower side. The wall portion 52extends from, among inner lateral surfaces of the case 51, a surface onthe axial direction first side towards the axial direction second side.A flow passage 50 a surrounded by the case 51, the heat sink 55, and thewall portion 52 is formed inside the liquid cooling portion 50. The flowpassage 50 a has a U-shape open towards the axial direction first side.

The liquid cooling portion 50 includes a first inflow and outflow port53 and a second inflow and outflow port 54. The first inflow and outflowport 53 and the second inflow and outflow port 54 are provided in asurface of the case 51 on the axial direction first side and so as to beseparated from each other in the width direction W. The first inflow andoutflow port 53 and the second inflow and outflow port 54 each connect aportion external to the liquid cooling portion 50 and the flow passage50 a to each other. The first inflow and outflow port 53 is connected toa first end of the flow passage 50 a. The second inflow and outflow port54 is connected to a second end of the flow passage 50 a. A refrigerantliquid flows into the flow passage 50 a of the present embodimentthrough the first inflow and outflow port 53. The refrigerant liquidthat has flowed inside the flow passage 50 a flows out through thesecond inflow and outflow port 54. The refrigerant liquid flows insidethe liquid cooling portion 50 in the above manner. The refrigerantliquid is not particularly limited and is water, for example.

By having the refrigerant liquid flow in the flow passage 50 a,components that are in thermal contact with the liquid cooling portion50 can be cooled. In the present embodiment, since the liquid coolingportion 50 is in thermal contact with the inverter unit 40 and thehousing 20, the inverter unit 40 and the housing 20 can be cooled withthe liquid cooling portion 50. Note that as illustrated in FIG. 3, atleast a portion of the protruding portion 21 b with which the liquidcooling portion 50 in the housing 20 is in thermal contact is disposedbelow the oil surface OS1 in the vertical direction Z. In other words,at least a portion of the protruding portion 21 b serving as the contactportion is disposed below the oil surface OS1. With the above, at leasta portion of an inner lateral surface of the protruding portion 21 b isin contact with the oil O stored in the first housing portion 21.Accordingly, by cooling the protruding portion 21 b with the liquidcooling portion 50, the oil O stored in the housing 20 can be cooled.

In the present embodiment, the oil O in a stored state can be cooled bythe liquid cooling portion 50 in the above manner; accordingly, comparedto a case in which a cooling device is disposed in the flow passagethrough which the oil O flows, the oil O can be sufficiently cooledeasily. Furthermore, since the liquid cooling portion 50 that cools theinverter unit 40 that adjusts the electric current supplied to the motor30 can be used, an increase in the size of the overall drive apparatus10 can be suppressed compared with a case in which a cooling device thatcools the oil O is provided separately. According to the presentembodiment, the drive apparatus 10 having a structure that is capable ofsufficiently cooling the oil O for cooling and that is capable ofsuppressing an increase in the size thereof can be obtained with theabove. Since the oil O can be cooled sufficiently, the motor 30 can becooled in a suitable manner with the oil O. Furthermore, since thenumber of parts of the drive apparatus 10 can be small, the labor andthe cost of assembling the drive apparatus 10 can be reduced.

Note that in the present specification, it is only sufficient that in“at least a portion of the contact portion being disposed below the oilsurface of the oil”, at least a portion of the contact portion isdisposed below the oil surface of the oil in at least one of the modesand positions among the modes and positions in which the drive apparatusis used. In other words, for example, in a state illustrated in FIG. 3,if at least a portion of the protruding portion 21 b is disposed belowthe oil surface OS1, then, when the drive apparatus 10 is positioned soas to be more inclined in the circumferential direction than theposition illustrated in FIG. 3, the entire protruding portion 21 b canbe disposed above the oil surface OS1. Furthermore, also in a case inwhich the oil surface OS1 changes in the vertical direction Z while theposition of the drive apparatus 10 does not change, it is onlysufficient that at least a portion of the protruding portion 21 b isdisposed below the oil surface OS1 in a range in the vertical directionZ in which the oil surface OS1 changes.

By providing the plurality of fins 55 b in the present embodiment, asurface area of the heat sink 55 in contact with the refrigerant liquidcan be increased. Accordingly, the heat of the power devices 43 b fixedto the bottom plate portion 55 a can be released through the pluralityof fins 55 b to the refrigerant liquid flowing through the flow passage50 a. With the above, the first inverter portion 43 can be cooledfurther readily with the liquid cooling portion 50.

At least a portion of the protruding portion 21 b that is the contactportion in the present embodiment is disposed below the rotor core 32.Accordingly, even if the oil surface OS1 is set below the rotor core 32in the manner described above, at least a portion of the inner lateralsurface of the protruding portion 21 b can be made to be in contact withthe oil O. Accordingly, the oil O stored inside the first housingportion 21 can be sufficiently cooled by cooling the protruding portion21 b with the liquid cooling portion 50 while preventing the oil O frombecoming a rotational resistance of the rotor core 32.

Furthermore, in the present embodiment, the protruding portion 21 b thatis the contact portion is the lower portion of the first housing portion21. Accordingly, the oil O stored in the first housing portion 21 can becooled with the liquid cooling portion 50. With the above, the motor 30can be efficiently cooled with the oil O. Note that in the presentspecification, “the lower portion of the first housing portion” includesa portion that is disposed below the center of the first housing portionin the vertical direction Z when the drive apparatus is disposed at aposition during ordinary use.

Furthermore, in the present embodiment, a portion of the inverter unit40 that is in thermal contact with the liquid cooling portion 50 is thefirst inverter portion 43. The first inverter portion 43 is disposed soas to be in thermal contact with and below the liquid cooling portion50. Accordingly, the housing 20 and the first inverter portion 43 caneasily interpose the liquid cooling portion 50 therebetween in thevertical direction Z, and both the housing 20 and the first inverterportion 43 can easily be in thermal contact with the liquid coolingportion 50. Furthermore, for example, as in the present embodiment, bymounting the power devices 43 b, which have a relatively large heatgenerating amount, in the first inverter portion 43, the portions in theinverter unit 40 that particularly generate heat can be readily cooledwith the liquid cooling portion 50.

Furthermore, in the present embodiment, the inverter unit 40 includesthe second inverter portion 44 disposed on the first direction firstside of the first housing portion 21. By disposing the first inverterportion 43 below and the second inverter portion 44 on the firstdirection first side of the first housing portion 21 in the abovemanner, compared to a case in which the entire inverter unit 40 isdisposed below or on the first direction first side of the first housingportion 21, a reduction in the size of the overall drive apparatus 10 isfacilitated. Furthermore, among the elements of the inverter unit 40, bygathering and installing the elements that have a relatively large heatgenerating amount in the first inverter portion 43, the inverter unit 40can be cooled efficiently even when the inverter unit 40 is split intotwo inverter portions. As described above, the present embodiment cansuppress the drive apparatus 10 from becoming large in size whileefficiently cooling the inverter unit 40 with the liquid cooling portion50.

The pipe portions 61 and 62 illustrated in FIG. 4 are connected to theliquid cooling portion 50 and the refrigerant liquid inside the liquidcooling portion 50 flows therethrough. The pipe portion 61 is connectedto the first inflow and outflow port 53. The pipe portion 62 isconnected to the second inflow and outflow port 54. The refrigerantliquid flows into the inner portion of the liquid cooling portion 50, inother words, into the flow passage 50 a, from the pipe portion 61through the first inflow and outflow port 53. The refrigerant liquidinside the flow passage 50 a flows out to the pipe portion 62 throughthe second inflow and outflow port 54. Although not shown, the pipeportions 61 and 62 are drawn into the second inverter case 42 a frominside the first inverter case 41 a and is drawn out to a portionexternal to the drive apparatus 10 from the second inverter case 42 a.The pipe portions 61 and 62 drawn out to the portion external to thedrive apparatus 10 is connected to a pump (not shown). The pumpcirculates the refrigerant liquid through the pipe portion 61, the flowpassage 50 a, and the pipe portion 62 in that order. Furthermore, thepipe portion 62 is connected to a radiator (not shown) at a portionexternal to the drive apparatus 10. The radiator cools the refrigerantliquid inside the pipe portion 62. With the above, the heat absorbed bythe oil O stored in the inverter unit 40 and the housing 20 can bereleased with the refrigerant liquid.

Driving force from the motor 30 is transmitted to the differential gear80 illustrated in FIG. 3 through the motor shaft 31. In more detail, thedifferential gear 80 is coupled to the motor shaft 31 through adeceleration mechanism, and a decelerated rotation of the motor shaft 31is transmitted. The differential gear 80 includes a connection holeportion 81 having a second central axis J2 at the center. The secondcentral axis J2 is parallel to the first central axis J1 and, in thefirst direction Y, is disposed on the opposite side of the secondinverter portion 44 with respect to the first central axis J1, in otherwords, is disposed on the first direction second side.

An output shaft disposed along the second central axis J2, for example,is connected to the connection hole portion 81. The differential gear 80is capable of outputting the driving force transmitted from the motorshaft 31 through the deceleration mechanism to an output shaft coupledto the connection hole portion 81. In other words, the differential gear80 is capable of outputting the driving force about the second centralaxis J2 to the output shaft. The output shaft is, for example, an axleof a vehicle.

In the present embodiment, the second central axis J2 is disposed at aposition that interposes the first central axis J1 with the secondinverter portion 44 in the first direction Y. Accordingly, the secondinverter portion 44, in other words, the second unit 42, can beprevented from being disposed at a position that overlaps the connectionhole portion 81 in the axial direction X. With the above, the outputshaft can be connected to the connection hole portion 81 easily.

The present invention is not limited to the embodiment described aboveand other configurations can be adopted. Note that in the descriptionhereinafter, description of components that are similar to those of theembodiment described above may be omitted by, for example, appropriatelyattaching the same reference numerals thereto.

The entire inverter unit 40 may be disposed below the first housingportion 21 or on either side of the first housing portion 21 in thefirst direction Y. In such a case, the first unit 41 and the second unit42 may be unified as a single unit. A portion of the liquid coolingportion 50 may be disposed above the oil surface OS1. Another liquidcooling portion that cools the second inverter portion 44 may beprovided in the second unit 42. In such a case, the another liquidcooling portion may be connected to the liquid cooling portion 50through the pipe portions 61 and 62, for example. Furthermore, theshapes of the plurality of fins 55 b may be shapes formed along the flowof the refrigerant liquid flowing in the flow passage 50 a. The bus bars70 and the pieces of conducting wire 35 a may be directly fixed to eachother without the crimped terminals 71 in between. The bus bars 70 andthe pieces of conducting wire 35 a may be, for example, directly fixedto each other with screws or may be directly fixed to each other bywelding.

As illustrated in FIGS. 7 and 8, in a drive apparatus 110 of the presentembodiment, a portion of a pipe portion 161 is disposed inside a firsthousing portion 121. In more detail, as illustrated in FIG. 8, the pipeportion 161 is inserted inside the first housing portion 121 through asurface of the first housing portion 121 on the axial direction firstside, is bent in a U -shape inside the first housing portion 121, and isprotruded to a portion external to the first housing portion 121 throughthe surface of the first housing portion 121 on the axial directionfirst side. With the above, the pipe portion 161 passes inside thehousing 120. Accordingly, the inner portion of the housing 120 can becooled with the pipe portion 161 and the oil O stored in the housing 120is readily cooled.

In the present embodiment, the oil O in a stored state can be cooled bythe pipe portion 161 in the above manner; accordingly, compared to acase in which a cooling device is disposed in the flow passage throughwhich the oil O flows, the oil O can be sufficiently cooled easily.Furthermore, since the pipe portion 161 connected to a liquid coolingportion 150 that cools the inverter unit 40 that adjusts the electriccurrent supplied to the motor 30 can be used, an increase in the size ofthe overall drive apparatus 110 can be suppressed compared with a casein which a cooling device that cools the oil O is provided separately.According to the present embodiment, the drive apparatus 110 having astructure that is capable of sufficiently cooling the oil O for coolingand that is capable of suppressing an increase in the size thereof canbe obtained with the above. Furthermore, similar to the firstembodiment, since the liquid cooling portion 150 can also cool the oil Ostored in the housing 120, the oil O can be cooled further.

The pipe portion 161 passes through a vertical direction lower side areainside the housing 120. Accordingly, it is easier to pass the pipeportion 161 through the oil O stored inside and on the lower side of thehousing 120 in the vertical direction Z. With the above, the oil Ostored in the housing 120 can be cooled further readily with the pipeportion 161.

Note that in the present specification, “the vertical direction lowerside area inside the housing” is any position in the inner portion ofthe housing below the center in the vertical direction Z. In otherwords, for example, in the first housing portion 121, a portion insidethe first housing portion 121 positioned below the center thereof in thevertical direction Z is the vertical direction lower side area insidethe housing. Furthermore, in the second housing portion 22, a portioninside the second housing portion 22 positioned below the center thereofin the vertical direction Z is the vertical direction lower side areainside the housing. In other words, the position of the verticaldirection lower side area inside the housing in the vertical direction Zis, in some cases, different depending on the housing portion, forexample.

In the present embodiment, the pipe portion 161 passes through thevertical direction lower side area inside the first housing portion 121.Accordingly, the pipe portion 161 can be readily passed into the housing120 at a portion below the oil surface OS1, and the pipe portion 161 cancool the oil O stored inside the first housing portion 121 in a suitablemanner. At least a portion of the pipe portion 161 disposed inside thehousing 120 is disposed below the oil surface of the oil O stored in thehousing 120, in other words, in the present embodiment, below the oilsurface OS1. Accordingly, the pipe portion 161 can be in contact withthe oil O and the oil O can be cooled further readily with therefrigerant liquid flowing through the pipe portion 161.

In the present embodiment, the entire portion of the pipe portion 161disposed inside the housing 120 is disposed below the oil surface OS1and passes inside the oil O. As illustrated in FIG. 7, the pipe portion161 disposed inside the housing 120 is disposed below the rotor core 32.In the present embodiment, the pipe portion 161 passes through an innerportion of a protruding portion 121 b.

As illustrated in FIG. 8, the pipe portion 161 protruding to a portionexternal to the first housing portion 121 from the inside of the firsthousing portion 121 is connected to the second inflow and outflow port54 of the liquid cooling portion 150. With the above, the refrigerantliquid flowing inside the pipe portion 161 flows into the liquid coolingportion 150 through the second inflow and outflow port 54. The pipeportion 162 is connected to the first inflow and outflow port 53 of theliquid cooling portion 150. With the above, the refrigerant liquidinside the liquid cooling portion 150 flows out into the pipe portion162 through the first inflow and outflow port 53. By connecting the pipeportions 161 and 162, and the first inflow and outflow port 53 and thesecond inflow and outflow port 54 to each other in the above manner, adirection of the refrigerant liquid flowing through the flow passage 50a inside the liquid cooling portion 150 is opposite to the direction inthe first embodiment.

As illustrated in FIG. 7, the drive apparatus 110 further includes apipe portion 163. Although not shown, the pipe portion 163 is connectedto the pipe portion 161 or the pipe portion 162 and is connected to theliquid cooling portion 150 through the pipe portion 161 or the pipeportion 162. The pipe portion 163 passes inside the housing 120. In moredetail, the pipe portion 163 passes through the vertical direction lowerside area inside the second housing portion 22. Accordingly, the oil Ostored in the second housing portion 22 is readily cooled with the pipeportion 163. At least a portion of the pipe portion 163 is disposedbelow the oil surface OS2 of the oil O stored in the second housingportion 22.

In the present embodiment, the first housing portion 121 is open towardsthe protrusion direction lower side. In more detail, the protrudingportion 121 b is open towards the protrusion direction lower side. Theopening of the protruding portion 121 b on the protrusion directionlower side is closed by a top plate portion 151 a of a case 151 of theliquid cooling portion 150. In other words, in the present embodiment, aportion of the liquid cooling portion 150 is also a portion of thehousing 120.

Note that in the present specification, “the liquid cooling portionbeing in thermal contact with the housing” includes a case in which therefrigerant liquid flowing inside the liquid cooling portion is capableof being in thermal contact with the housing. In the present embodiment,since the top plate portion 151 a constitutes a portion of the firsthousing portion 121, the refrigerant liquid flowing inside the liquidcooling portion 150 is in thermal contact with the top plate portion 151a that constitute a portion of the first housing portion 121.Accordingly, the liquid cooling portion 150 is in thermal contact withthe housing 120. With the above, similar to the first embodiment, sincethe liquid cooling portion 150 can cool the oil O stored in the housing120, the oil O is cooled further readily. Particularly in the presentembodiment, since the refrigerant liquid is directly in contact with thetop plate portion 151 a that constitutes a portion of the first housingportion 121 that stores the oil O, the heat of the oil O is absorbedfurther readily with the refrigerant liquid and the oil O is cooledfurther readily.

The top plate portion 151 a is fixed to an end portion of the protrudingportion 121 b on the protrusion direction lower side with screws.Although not shown, a sealing member is disposed between the top plateportion 151 a and the end portion of the protruding portion 121 b on theprotrusion direction lower side. The sealing member is a formed-in-placegasket (FIPG), for example. With the above, the oil O inside the firsthousing portion 121 can be prevented from leaking to a portion externalto the housing 120.

As illustrated in FIG. 9, in a drive apparatus 210 of the presentmodification, a first housing portion 221 of a housing 220 includes awindow portion 221 c. The window portion 221 c is an opening portionprovided in a surface of the first housing portion 221 on the axialdirection first side. The window portion 221 c connects an inner portionof the first housing portion 221 and a portion external to the firsthousing portion 221 to each other. The window portion 221 c has arounded rectangle shape extending in the width direction W.

The housing 220 includes a lid portion 223 that covers the windowportion 221 c. The lid portion 223 has a plate shape orthogonal to theaxial direction X. The shape of the lid portion 223 viewed in the axialdirection X is a rounded rectangle shape extending in the widthdirection W. The lid portion 223 closes the window portion 221 c bybeing fitted into the window portion 221 c. A material of the lidportion 223 is, for example, rubber or metal. A sealing member such as,for example, an FIPG is disposed between the window portion 221 c andthe lid portion 223. With the above, the oil O can be prevented fromleaking to a portion external to the first housing portion 221 through agap between the window portion 221 c and the lid portion 223.

The lid portion 223 includes hole portions that penetrate the lidportion 223 in the axial direction X at both end portions in the widthdirection W. A portion of the pipe portion 161 inserted inside the firsthousing portion 221 from a portion external to the first housing portion221, and a portion of the pipe portion 161 that is protruded to aportion external to the first housing portion 221 from inside the firsthousing portion 221 are passed through the hole portions of the lidportion 223. A sealing member such as, for example, an FIPG is disposedbetween each of the hole portions of the lid portion 223 and the pipeportion 161. With the above, the oil O can be prevented from leaking toa portion external to the first housing portion 221 through a gapbetween the hole portions of the lid portion 223 and the pipe portion161.

According to the present modification, since the window portion 221 c isprovided, the pipe portion 161 is really passed into the first housingportion 221. Specifically, in a state in which the pipe portion 161 ispassed through the hole portions of the lid portion 223 and in which thelid portion 223 is fixed to the pipe portion 161, a portion in the pipeportion 161 bent in a U-shape is inserted inside the first housingportion 221 through the window portion 221 c. Subsequently, the pipeportion 161 is inserted towards the axial direction second side and thelid portion 223 is fitted into and fixed to the window portion 221 c.With the above, a portion of the pipe portion 161 can be readilydisposed inside the first housing portion 221, and the pipe portion 161can be passed through into the first housing portion 221 in a readilymanner.

In the present modification, different from the drive apparatus 110illustrated in FIG. 8, the refrigerant liquid flows into the liquidcooling portion 150 through the pipe portion 162, and the refrigerantliquid that has flowed inside the liquid cooling portion 150 flows outthrough the pipe portion 161. In other words, the direction in which therefrigerant liquid flows in the pipe portions 161 and 162 and the liquidcooling portion 150 in the present modification is opposite to that inthe drive apparatus 110 illustrated in FIG. 8. With the above, therefrigerant liquid fed from a pump (not shown) can be made to flowinside the liquid cooling portion 150 before being made to flow insidethe first housing portion 221. Accordingly, a temperature of therefrigerant liquid flowing inside the liquid cooling portion 150 can belower and the first inverter portion 43 can be cooled in a furthersuitable manner.

As illustrated in FIG. 10, in a drive apparatus 310 of the presentembodiment, a liquid cooling portion 350 is fixed to a lateral surfaceof the protruding portion 21 b on the width direction first side. Afirst inverter portion 343 is fixed to a lateral surface of the liquidcooling portion 350 on the width direction first side. The driveapparatus 310 includes a second liquid cooling portion 356. The secondliquid cooling portion 356 is fixed to a lateral surface of theprotruding portion 21 b on the width direction second side. With theabove, the second liquid cooling portion 356 is in thermal contact withthe housing 20. The refrigerant liquid passes inside the second liquidcooling portion 356. A structure of the second liquid cooling portion356 can be similar to a structure of the liquid cooling portion 50illustrated in FIG. 6, for example.

As illustrated in FIG. 10, the drive apparatus 310 includes pipeportions 361, 362, and 363. The pipe portion 361 is connected to thesecond liquid cooling portion 356 and makes the refrigerant liquid flowinto the second liquid cooling portion 356. The pipe portion 362connects the second liquid cooling portion 356 and the liquid coolingportion 350 to each other. The refrigerant liquid inside the secondliquid cooling portion 356 flows out to the inside of the pipe portion362 and flows into the liquid cooling portion 350 through the pipeportion 362. The pipe portion 363 is connected to the liquid coolingportion 350. The refrigerant liquid inside the liquid cooling portion350 flows out to the inside of the pipe portion 363.

According to the present embodiment, since the oil O stored in the firsthousing portion 21 can be cooled with the liquid cooling portion 350 andthe second liquid cooling portion 356 from both sides in the widthdirection W, the oil O can be cooled in a further suitable manner.

Note that the direction in which the refrigerant liquid flows in thepipe portions 361, 362, and 363, the liquid cooling portion 350, and thesecond liquid cooling portion 356 may be a direction opposite to thedirection described above. In other words, the refrigerant liquid mayflow from the pipe portion 363, through the liquid cooling portion 350,the pipe portion 362, and the second liquid cooling portion 356, and tothe pipe portion 361 in that order. In such a case, the temperature ofthe refrigerant liquid flowing through the inner portion of the liquidcooling portion 350 with which the first inverter portion 343 is inthermal contact can be lowered further. Accordingly, the first inverterportion 343 can be cooled further with the liquid cooling portion 350.

In a drive apparatus 410 of the present embodiment illustrated in FIG.11, a pipe portion 461 extends in a U-shape open towards the axialdirection first side. The pipe portion 461 surrounds outer sides of theprotruding portion 21 b. In more detail, the pipe portion 461 surroundsthe protruding portion 21 b by being in contact with a lateral surfaceof the protruding portion 21 b on the width direction first side, asurface of the protruding portion 21 b on the axial direction secondside, and a lateral surface of the protruding portion 21 b on the widthdirection second side. With the above, the pipe portion 461 is inthermal contact with the outer lateral surfaces of the first housingportion 21, in other words, with the outer lateral surfaces of thehousing 20. Accordingly, in the present embodiment, in addition to theliquid cooling portion 50, the housing 20 can be cooled from the outersides with the pipe portion 461 as well. Accordingly, the oil O storedin the housing 20 can be cooled further.

In the present embodiment, the portions with which the pipe portion 461is in thermal contact are the outer lateral surfaces of the protrudingportion 21 b. The outer lateral surfaces of the protruding portion 21 bare outer lateral surfaces of the first housing portion 21 in thevertical direction lower side area. In other words, the pipe portion 461is in thermal contact with the outer lateral surfaces of the verticaldirection lower side area of the housing 20. With the above, the oil Ostored in the housing 20 can be cooled further readily with the pipeportion 461.

Note that the pipe portion 461 may be in thermal contact with an outerlateral surface of the housing 20 other than that of the protrudingportion 21 b. For example, the pipe portion 461 may be in thermalcontact with an outer lateral surface of the second housing portion 22.Furthermore, similar to the second and third embodiments, the driveapparatus 410 may be provided with a pipe portion that passes inside thehousing 20.

In each of the embodiments described above, the inflow and outflow ofthe refrigerant liquid with respect to the liquid cooling portion areperformed through the same surface of the liquid cooling portion in theaxial direction X; however, it is not limited to the above. As in aliquid cooling portion 550 illustrated in FIG. 12, the inflow and theoutflow of the refrigerant liquid with respect to the liquid coolingportion may be performed through a surface on the opposite side of theliquid cooling portion in the axial direction X. As illustrated in FIG.12, in the liquid cooling portion 550, a first inflow and outflow port553 is provided in a surface of a case 551 on the axial direction firstside. A second inflow and outflow port 554 is provided in a surface ofthe case 551 on the axial direction second side. With the above, forexample, the refrigerant liquid that has flowed from the axial directionfirst side into a flow passage 550 a through the first inflow andoutflow port 553 flows out of the second inflow and outflow port 554towards the axial direction second side.

The first inflow and outflow port 553 is disposed in a surface of thecase 551 on the axial direction first side and at the middle of thesurface in the width direction W. The second inflow and outflow port 554is disposed in a surface of the case 551 on the axial direction secondside and at the middle of the surface in the width direction W. Notethat in the liquid cooling portion 550, the refrigerant liquid may bemade to flow through the second inflow and outflow port 554 to the flowpassage 550 a and the refrigerant liquid inside the flow passage 550 amay be made to flow out through the first inflow and outflow port 553.

Furthermore, in the embodiments described above, the contact portionwith which the liquid cooling portion in the housing is in thermalcontact is a portion of the first housing portion; however, it is notlimited to the above. The contact portion may be a portion of the secondhousing portion. In such a case, the liquid cooling portion may beconfigured as a liquid cooling portion 650 illustrated by a two-dotchain line in FIG. 3. The liquid cooling portion 650 is in thermalcontact with and is fixed to the lower end portion of the second housingportion 22. In other words, the contact portion of the housing 20 withwhich the liquid cooling portion 650 is in thermal contact is a lowerportion of the second housing portion 22. With the above, the oil Ostored in the second housing portion 22 can be sufficiently cooled withthe liquid cooling portion 650. In such a configuration, for example, aninverter unit 640 is fixed to a surface of the liquid cooling portion650 on the lower side.

Features of the above-described preferred embodiments and themodifications thereof may be combined appropriately as long as noconflict arises.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

1-10. (canceled)
 11. A drive apparatus comprising: a motor that includesa motor shaft disposed along a first central axis that extends in onedirection; a housing that includes a first housing portion housing themotor and that is capable of storing oil; and a liquid cooling portiondisposed in thermal contact with an inverter electrically coupled to themotor, the liquid cooling portion including a refrigerant liquid flowingtherein; wherein the housing includes a contact portion with which theliquid cooling portion is in thermal contact; and at least a portion ofthe contact portion is disposed below an oil surface of the oil storedin the housing.
 12. The drive apparatus according to claim 11, whereinthe first housing portion is capable of storing oil; and the contactportion is a lower portion of the first housing portion.
 13. The driveapparatus according to claim 12, wherein the inverter includes a firstinverter portion disposed so as to be in thermal contact with and belowthe liquid cooling portion.
 14. The drive apparatus according to claim13, wherein the inverter includes a second inverter portion disposed ona first side of the first housing portion in a first directionorthogonal to a vertical direction.
 15. The drive apparatus according toclaim 14, further comprising: a differential gear to which driving forcefrom the motor is transmitted through the motor shaft; wherein thehousing houses the differential gear and includes a second housingportion capable of storing oil; an axial direction of the first centralaxis is a direction orthogonal to both the vertical direction and thefirst direction; the differential gear is capable of outputting adriving force about a second central axis parallel to the first centralaxis; and the second central axis is disposed, with respect to the firstcentral axis, on a side opposite to the second inverter portion in thefirst direction. a differential gear to which a driving force from themotor is transmitted through the motor shaft; wherein the housing housesthe differential gear and includes a second housing portion capable ofstoring oil; and the contact portion is a lower portion of the secondhousing portion.
 17. The drive apparatus according to claim 11, furthercomprising: a pipe portion connected to the liquid cooling portion, therefrigerant liquid inside the liquid cooling portion flowing in the pipeportion; wherein the pipe portion extends inside the housing.
 18. Thedrive apparatus according to claim 11, further comprising: a pipeportion connected to the liquid cooling portion, the refrigerant liquidinside the liquid cooling portion flowing in the pipe portion; whereinthe pipe portion is in thermal contact with an outer lateral surface ofthe housing.
 19. The drive apparatus according to claim 11, wherein thefirst housing portion is capable of storing oil; the motor includes arotor core fixed to the motor shaft; and the rotor core is disposedabove an oil surface of the oil stored in the first housing portion. 20.The drive apparatus according to claim 11, further comprising: a bus barelectrically coupling the inverter and the motor to each other; whereinthe motor includes: a rotor core fixed to the motor shaft; and a statorthat opposes the rotor core in a radial direction with a gap in between;the stator includes: a stator core; and a plurality of coils mounted inthe stator core; the bus bar extends inside the housing and is coupledto the coils through crimped terminals; and the crimped terminals aredisposed above an oil surface of oil stored in the housing.